In the color development of a silver halide light-sensitive material after imagewise exposure, an aromatic primary amine developing agent oxidized by the silver halide reacts with dye-forming-couplers to form color images.
In this process, color reproduction utilizing the subtractive color method is generally carried out, and images of yellow, magenta and cyan colors bearing a complementary relationship to blue, green and red tints, respectively, are formed.
Hitherto, phenols and naphthols have been used as cyan color image-forming couplers in most cases. However, the preservability of color images produced from conventional phenols and naphthols have some unsolved problems. For instance, color images produced from the cyan couplers of the 2-acylaminophenol type, as disclosed in U.S. Pat. Nos. 2,367,531, 2,369,929, 2,423,730 and 3,772,002, generally are inferior with respect to heat resistance; and those produced from cyan couplers of the 2,5-diacylaminophenol type, as disclosed in U.S. Pat. Nos. 2,772,162 and 2,895,826, generally are inferior in light resistance. In addition, color images obtained from the cyan couplers of the 2-ureidophenol type are, in general, inferior with regard to light resistance, and those of the cyan coupler of 1-hydroxy-2-naphthamide type are generally insufficient in both heat resistance (particularly to high temperature and high humidity resistance) and light resistance, as disclosed in U.S. Pat. Nos. 3,446,622 and 4,333,999.
Moreover, the cyan couplers of the 2-acylaminophenol type, including those represented by formula (I) of this invention had showed defects in that they tended to cause a lowering of their color-forming power when a developer free from benzyl alcohol having a heavy load of environmental pollution was used. Accordingly, when it was intended to ensure a high color-forming power to such couplers, cyan color formation occurred in uncolored areas in a lapse of time resulting in generation of color stain.
On the other hand, though the examples of using di- to tricarboxylic acid esters as high boiling point organic solvents have been disclosed in JP-B-53-12378 (the term "JP-B" as used herein refers to an "examined Japanese patent publication"), JP-A-54-106228 (the term "JP-A" as used herein refers to a "published unexamined Japanese patent application") and JP-A-54-118246, the achieved fastness was still insufficient in the combined use with the phenol type cyan couplers having methyl or methoxy groups at the 5-position, which were specified therein.